Signaling system



June 3, 1969 F. E. wELD SIGNALING SYSTEM sheet ors Filed July 9, 1965I1lillllllillmmmwiwfllilIIII!! ATTORNEYS June 3, 1969 F. E. wl-:LD

SIGNALING SYSTEM ors Sheet Filed July 9, 1965 Om .E

ATTORNEYS sheet of 5 June 3, 1969 F. E. WELD SIGNALING SYSTEM Filed July9, 1965 k 0S om. o m mw @E u mm. w, U TE m mw a L v sa 2956 2.522 ME aomg com of o3 oom .be o H M v n w T m m ,qm @E F 7 m v VL B ml LPPATTORNEYS F. E. WELD SIGNALING SYSTEM June 3, 1969 Sheet Filed July 9.1965 INVENTOR.

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vi M2525 mwmn -moa m ATTORNEYS Sheet Filed July 9, 1965 FOSTER E. wELDimq ody ATTORNEYS United States Patent() U.S. Cl. 340-287 13 ClaimsABSTRACT F THE DISCLOSURE There is provided a signaling system whichincludes a plurality of remotely located system transmitters, eachincluding code signaling means, driving means for driving said codesignaling means, and control means for activating the driving means; aconventional fire alarm transmitter having normally-closed signalingcontacts connected in series with the signaling means of the systemtransmitters by a conductor extending from a central station; a centralstation pulse generator for transmitting driving impulses to anactivated system transmitter through a pair of conductors extending fromthe central station; and, a pulse generator controller for energizingthe pulse generator when a system transmitter is activated and noconventional lire alarm transmitter has been actuated.

This invention pertains to the art of signaling systems and, moreparticularly, to an improved signaling system in which transmitterdriving impulses are transmitted from a central station to remote codetransmitters which transmit coded signal impulses back to the centralstation to actuate recording or alarm devices in accordance with thecoded signal impulses.

'Ihe present invention is particularly applicable as a tire, emergencyand/or watch signaling system and will be described with -particularreference thereto; although it will be appreciated that the inventionhas broader applications.

A signaling system similar to that of the present invention is describedand illustrated in my U.S. Patent No. 2,355,934. That system generallyincludes a plurality of remotely located transmitters, each including anormally open activating switch and a coded cam wheel driven by aratchet motor for actuating normally closed code signaling contacts; acentral station pulse generator for transmitting impulses of alternatingpositive and negative polarity to an activated transmitter, the positiveimpulses serving to drive the ratchet motor and the negative impulsesserving as signaling impulses in dependence on the active transmittercoded cam wheel to energize a central station alarm or recording devicein accordance with the code; and, three conductors extending from thecentral station with one conductor connected in series with the codesignaling contacts and the other two conductors connected to eachtransmitter ratchet motor through its activating switch.

The driving power for each remote transmitter of the above system isobtained from the pulse generator at the central station. One of theproblems of the system described above is that it includes no provisionsto permit compatibility with a conventional self-powered re alarmtransmitter, i.e., a positive, noninterfering, successive, automaticground, prewound clockwork driven transmitter such as E. W. BlissCompany, Gamewell Divisions Three Fold Manual or Automatic Master Box,catalog numbers 700() (Manual) and 9000 (Master), Series. It isimportant that such a system be compatible with conventionalself-.powered transmitters since many users of the system may own largequantities of such transmitters and would like to use them in thesystem. For a system 3,448,443 Patented June 3, 1969 ACe similar to thatdescribed above to be compatible with a conventional self-powered realarm transmitter, provisions should be made to obtain noninterferingsignaling operation between the conventional self-powered trans--mitters and the systems remotely powered transmitters. Moreparticularly, provisions should be made to prevent the pulse generatorfrom transmitting driving impulses to an activated system transmitteruntil an actuated conventional fire alarm transmitter has completed itssignaling operation.

The present invention is directed toward a signaling system similar tothat as described above, but which is compatible with conventionalself-powered tire alarm transmitters and which includes provisions forobtaining noninterfering signaling operation between the systemstransmitters and the conventional self-powered transmitters, therebyovercoming the noted disadvantages, and others, of previous signalingsystems.

In accordance with the -present invention the noninterfering signalingsystem includes a plurality of remotely located, remotely powered systemtransmitters, each including code signaling means, driving means, suchas a ratchet motor, for driving same, and a control means for activatingthe driving means; a self-powered conventional re alarm transmitterhaving normally closed signaling contacts; circuit means electricallyconnecting said signaling contacts in series with the signaling means ofthe system transmitters and including a conductor extending from acentral station; a central station pulse generator means located at thecentral station for transmitting driving impulses to the driving meansof an activated system transmitter through circuit means including apair of conductors extending from the central station to said systemtransmitters; and, pulse generator control means located at the centralstation and coupled to the pulse generator means, the pulse generatorcontrol means including circuit means for energizing the pulse generatormeans only when a system transmitter is activated after a predeterminedperiod of time has elapsed from the last actuation of a conventionalalarm transmitter so that non-interfering operation is obtained betweenthe system transmitters and the conventional alarm transmitter.

In accordance wih another aspect of the present invention the pulsegenerator controller serves to time a predetermined period of time uponactuation of a conventional re alarm transmitter before energizing thepulse generator, the predetermined period of time being greater than thetime duration of a closed circuit in the iirst conductor circuit due toclosure of the fire alarm transmitter signaling contacts duringsignaling operation of such transmitter to thereby prevent energizationof an activated system transmitter until the re alarm transmittercompletes its signaling operation.

In accordance with a still further aspect of the present invention, adetector circuit is provided for the signaling system for energizing acontrol means of a system transmitter; the detector circuit includes adetector conductor having a relay coil and a bucking coil connectedtogether in series opposition, and a normally open detector switchconnected across the bucking coil.

The primary object of the present invention is to provide an improvedsignaling system having compatibility with a conventional self-poweredre alarm transmitter.

Another object of the present invention is to provide a signaling systemhaving provisions for obtaining noninterfering signaling operationbetween system transmitters and conventional self-powered iire alarmtransmitters.

A still further object of the present invention is to provide animproved signaling system utilizing solid state devices, such astransistors, for low current and, hence, power requirements foreconomically eflicient operation.

These and other objects and advantages of the invention will becomeapparent from the lfollowing description of the preferred embodiment ofthe invention as read in connection with the accompanying drawings inwhich:

FIGURES 1 and 1A are system block diagrams of the preferred embodimentof the invention;

FIGURE 2 is a schematic diagram illustrating a system transmitter;

FIGURE 3 is a schematic circuit diagram of the central station equipmentillustrated in block diagram form in FIGURE 1;

i FIGURES 4A, 4B, 4C, 4D and 4E are waveforms of voltage versus timeillustrating one aspect `of the operation of the invention;

FIGURES 5A, 5B and 5C are waveforms of voltage versus time illustratinganother aspect of the operation of the invention; and,

FIGURES 6A and 6B are waveforms of amplitude versus revolutionsillustrating a still further aspect of the operation of the invention.

Referring now to the -drawings wherein the showings `are for the purposeof illustrating a preferred embodiment of the invention and not for thepurpose of limiting same, FIGURE 1 is a block diagram illustrating thesignalling system and generally includes a plurality of remotetransmitters XTR-1 through XT R-7 a pair of conventional fire alarmtransmitters A .and B; a pair of transmitter lines TL and LN extendingfrom a central station C; a signal line SL extending from centralstation C; a detector line DL extending from central station C andincluding in circuit therewith a pair of detectors 'D and E; emergencyrelay equipment ER at the central station C and including a ground timedelay unit GTD, emergency grounding relay circuitry EGR, transmittercircuit supervisory relay circuitry TSR, emergency connect relaycircuitIy ECR, and a direct current voltage supervisory relay circuitDCR; box and transmitter circuitry AR including detector circuitsupervisory relay circuitry DSR, alarm supervisory relay circuitry ASR,pulse generator circuitry PGR, transmitter alarm relay circuitry TAR,signal supervisory relay circuitry SSR, and signal alarm relay circuitrySAR; a console recorder CR at the central station C; power supplycircuitry at the central station C including an alternating currentvoltage source F, a battery H, a battery charger I, and three 24 voltD.C. to 110 volt D.C. converters CV-1, CV-Z and CV-3; and, an alarm lineAL having in circuit therewith alarm devices AL-I, AL-Z and AL-3.

A The transmitter line TL extends from the positive side of converterCV-l through normally closed pulse generator contacts PGR-1, transmittercircuit alarm relay coil TAR-C, transmitter line terminal TL+ and islooped to define three open transmitter loops 10, 12 and 14, throughterminal LN-l, through a high impedance relay coil TSR-C having animpedance on the order of 10 kilohms, back through the transmitter loops10, 12 and 14, from terminal LN- to terminal TL-, and thence through thecentral station C to the negative side of converter CV-l. Preferably,the maximum resistance of each loop of the transmitter line is on theorder of 400 ohms.

normally closed emergency ground relay contacts EGR-1 to the negativeside of converter CV-1. Preferably, the maximum line resistance ofsignal line SL is on the order of 400 ohms and that supervisory currenton the order of 100 milliamperes normally ows through the signa line SL.Y

The detector line DL extends from the positive side of the 24 volt D.C.to 110 volt D C. converter CV-3, through a detector supervisory relaycoil DSR-C, and thence through a line current adjusting rheostat RV-3, a0 to 50 milliampere ammeter 22, detector line terminal DL-|-, and isthen looped twice to dene a first detector double loop 24, and is againlooped twice to define a second `detector double loop 26, and thenextends through detector line terminal DL- to the negative side ofconverter CV-3. Detectors D and E, respectively associated with thedetector loops 24 and 26, are substantially identical and, accordingly,the following description will be made with reference only to detectorD.

Detector D includes a detector relay DR having a relay coil 30 and abucking coil 28 connected together in series opposition so that currentnormally owing from Adetector line terminal DL+ to detector lineterminal DL- through coils 28 and 30 will not energize detector relayDR. The detectors D and E each include normally open detector contacts34 associated with detector relay IDR and in series circuit withtransmitter coils XTR-C of transmitters XTR-3 and XTR-7 acrosstransmitter lines TL and LN. Detector D also includes normally opendetector contacts 32 connected across detector relay bucking coil 28.The detector contacts 32 may take any suitable form, such as abimetallic switch or a manually operated switch, etc. Preferably, themiximum total resistance of the Adetector line DL is on the order of3,000 ohms and the current normally flowing through the detector line DLis on the order of 40 milliamperes.

The alarm line AL extends from the positive side of the 24 volt D.C. to110 volt D.C. converter CV-2, through alarm supervisory relay coilASR-C, normally closed supervisory :alarm relay contacts SAR-C, througha line current adjusting rheostat RV-Z, a 0 to 200 milliampere ammeter36, through the alarm terminal AL{, through the series connected alarmdevices AL-1 through AL-3, and from the alarm terminal AL- to thenegative side of converter CV-Z.

Transm tters The transmitters XTR-1 through XTR-7, illustrated in FIGURE1, are substantially the same and each takes the form, for example, oftransmitter XTR-1, illustrated in detail in FIGURE 2. Transmitter XTR-1includes a driving coil XTR-C of -a ratchet motor 38 including a ratchetwheel 40, a driving pawl 42 magnetically associated with coil XTR-C, acam carrying shaft 44 extending from ratchet wheel 40 and having mountedthereon a coding wheel 46, a transfer wheel 48, a Geneva gear actuatingwheel 50 having a pin 52 extending therefrom for purposes of actuating aGeneva wheel 54, and an off-normal cam wheel 56. The code wheel 46 isprovided with a plurality of radially extending cam lobes 58 which serveto engage movable contact 60 of normally closed signalling contacts SL-1connected in series circuit with The supervisory line SL extends fromthe junction of i the normally closed pulse generator relay contactsPGR-1 and the normally de-energized transmitter alarm relay coil TAR-C,through a series circuit including normally energized supervisory alarmrelay coil SAR-C, normally energized signal supervisory relay coilSSR-C, through a line current adjusting rheostat RV-1, a 0 to 200milliampere ammeter 1-6, through a signal line terminal SL+, throughnormally closed signal contacts SL-l through SL-7 of transmitters XTR-1through XTR-7, respectively, through normally closed signaling contacts18 and 20 of conventional fire alarm transmitters A and B, respectively,signal line terminal SL, and thence through the signaling line SL. Thetransfer cam wheel 48 includes a cam lobe 62 extending radially outwardtherefrom and serves to engage a movable contact 64 of a single pole,double throw transfer switch S-2. Contact 64 is connected to transmittercoil XTR-C. The transfer switch S-2 also includes a stationary contact66 connected to stationary contact 76 of detector switch S-1 and asecond stationary contact 68 connected to a stationary contact 70ofdetector switch S-l. Detector switch S-1 includes a movable contact 72connected to transmitter line terminal LN- through the anode to cathodecircuit of a diode 74.

vThe Geneva gear cam wheel S4 includes a radially extending cam lobe 78which serves to engage and displace a movable contact 80 from astationary contact 82 to a second stationary contact 84 of a singlepole, double throw Geneva gear driven switch S-3. Stationary contact 84is connected to transmitter coil XT R-C and stationary contact 82 isconnected to the cathode side of diode 74 in transmitter line LN.

The off-normal cam wheel 56 is provided with a pair of diametricallyopposed notched portions 86 and 88 for receiving a cam wiper portion ofmovable Contact 90 of oi-normal single pole, double throw switch S-4.The switch S-4 also includes a stationary contact 92 connected to.transmitter coil XT R-C and another stationary contact 94 normally inengagement with contact 90 and connected to the movable contact 80 ofGeneva switch S-3, through contacts 71 and 75 of a single pole, doublethrow switch S-5 having another contact 73 connected to the cathode sideof diode 74. The detector switch S-1, illustrated in FIGURE 2 as asingle pole, double throw switch, may take various `forms either as a.manually operable switch or as normally open relay contacts 34,illustrated in conjunction with detectors D and E in FIGURE 1. SwitchS-1 should be double throw type, with connections to contacts of the camoperated transfer switch S-2, as shown by FIGURE 2, whenever the switchS-l may remain in abnormal position for a time longer than the time totransmit the signal. This is necessary in order for the transmitter tostop at the completion of each transmission. For manually operatedtransmitters, where the starting switch S-l is not likely to be heldclosed longer than the transmission time of a signal, the switch S-1 maybe a single normally open contact and the transfer switch S-2 may beomitted, in which case, contact 76 of S-1 would be connected directly totransmitter coil XTR-C, instead of through contacts 64 and 66 of S-2. Anoninterference coil NI-C of a noninterference relay NIR is connected inparallel with transmitter coil XTR-C and is magnetically connected withnormally closed noninterference contact NI-1 connected in series circuitin transmitter line TL and in parallel with a diode 96, poled as shownin FIGURE 2.

Central station equipment Reference is now made to FIGURE 3 in which theequipment located at central station C is illustrated in schematiccircuit diagram form. For purposes of facilitating the understanding ofthe invention, the lfollowing description will commence with describingthe components shown on the left hand side of FIGURE 3, proceeding tothose shown on the right hand side of FIGURE 3.

Pulse generator A pulse generator PG is connected across battery H andserves to periodically energize pulse generator relay coil PGR-C ofpulse generator relay circuit PGR for purposes of periodically openingthe normally closed contacts PGR-1 in the transmitter line TL. The pulsegenerator PG includes generally a bistable multivibrator circuit 100 anda trigger source for driving the multivibrator taking the form of aunijunction relaxation oscillator 102. The multivibrator circuit 100includes a pair of silicon controlled rectiers Q-2 and Q-3 connectedtogether in ip-op fashion and having their cathode' circuits connecteddirectly to the negative side of battery H and their anode circuitsconnected to the positive side of battery H throughY resistorsR-4 andR-S, respectively. A smoothing capacitor C-S is connected in parallelacross battery H between the battery and the multivibrator circuit 100.The anodes of rectifiers. Q-Z and Q-3 are connected together by acapacitor C-4 and a diode D-l, poled as shown in FIGURE 3, is connectedbetween the junction of the capacitor and resistor R5 to the positiveside of battery H. The gates of rectifiers Q-2 and Q-3 are connectedtogether by series connected capacitors C-Z and C-3, having theirjunctions connected to the negative side of battery H through a loadresistor R-3 of the relaxation oscillator 102. The gates of rectifiersQ-2 and Q-3 are also connected to the negative side of battery H throughresistors R-6 and R-7 respectively. A Zener diode Z-1, poled as shown inFIGURE 3, is connected between the negative side of ybattery H and thepositive side of battery H through a resistor R-8. The junction of thecathode side of Zener diode Z-1 and resistor R-8 is connected to baseB-2 of unijunction transistor Q-1 of the relaxation oscillator circuit102 through a resistor R-2. Transistor Q-1 also has a base B-1 connectedto the junction of capacitors C-2 and C-3 of multivibrator circuit 100,and a timing capacitor C-l connected between its emitter and thenegative side of battery H. A pair of variable timing resistors 104 and106 are connected together in series between the emitter of transistorQ-l and the positive side of battery H through resistor R-l and resistorR-8. The emitter of transistor Q-l is also connected to the negativeside of battery H through a resistor R-9 connected in Series withnormally closed contacts PCR-1 of pulse control relay circuit PCR,normally closed restore switch S-ZB and normally closed relay contactsTAR-1 of transmitter alarm relay circuit TAR. The normally closedcontacts TAR-1 are connected in parallel with normally open relaycontacts SAR-1 of signal alarm relay circuit SAR. The junction ofnormally closed relay contacts PCR-1 and resistor R-9 is connected tothe junction of variable resistors 104 and 106 through normally openrelay contacts PCR-2 of the pulse control relay circuit PCR. The outputof pulse generator PG is taken from the anode of rectier Q-3 and isconnected to relay coil PGR-C and also to relay coil PCR-C of the pulsecontrol relay circuit PCR through the cathode to anode circuit of diodeD-2. The relay circuit PCR is a slow release relay and includes normallyopen relay contacts PCR-3 connected in series with coil PCR-C acrossbattery H through normally open relay contacts TAR-2 of the transmitteralarm circuit TAR. The relay circuits PCR and TAR also include normallyclosed relay contacts PCR-4 and TAR-3 connected together in series forpurposes as will be described in greater detail hereinafter.

The signal alarm relay circuit SAR includes a relay coil SAR-C in seriescircuit in the signal line SL, normally open relay contacts SAR-1connected in parallel with normally closed relay contacts TAR-1, andnormally open relay contacts SAR-2 connected from the positive side ofbattery H to resistor R10 of a ground time delay circuit GTD.

Ground time delay circuit The ground time delay circuit generallyincludes a unijunction relaxation oscillator and a freerunningrelaxation oscillator 107 for driving a silicon controlledrectifier Q-6. The unijunction relaxation oscillator circuit 105includes a unijunction transistor Q4 having an emitter connected toresistor R-10 through the parallel path including diode D-3 connected inparallel with series connected resistor R-11 and varia-ble resistorRV-4. A timing capacitor C-6 is connected from the emitter ofunijunction transistor Q4 to the negative side of battery H throughnormally closed restore switch S-ZA. Transistor Q4 also has a first baseB-1 connected to restore switch S-2A through a load resistor R-12 and asecond base B-2 connected to the positive side of battery H through areverse bias resistor R-13.

The free running oscilator 107 includes a unijunction transistor Q-Shaving an emitter connected to base B-2 of transistor Q-4 through acapacitor C-7, a first base B-l directly connected to switch S-ZA and asecond base B-2 connected to the positive side of battery H through areverse bias resistor R-14. A timing capacitor C-8 is connected betweenthe emitter and base B--l of transistor Q-S, and is also connected inseries with a resistor R-15 to the positive side of battery H. Loadresistor R-12 is connected in parallel with a capacitor C-9 across thegate to cathode circuit of a silicon controlled rectiier Q-6 having ananode connected to the positive side of battery H through a pilot lampPL-4. A diode D4, poled as shown in FIGURE 3, is connected from theanode of silicon controlled rectifier Q-6 to the positive side ofbattery H, and a Zener diode Z-2, poled as shown in FIGURE 3, isconnected across the anode to cathode circuit of rectifier Q-6.

Emergency ground relay circuitry The emergency ground relay circuit EGRincludes a relay coil EGR-C connected across battery H through the anodeto cathode circuit of silicon controlled rectier Q-6 of ground timedelay circuit GTD and the normally closed restore switch S-ZA. Relaycircuit EGR also includes normally closed relay contacts EGR-1 in seriescircuit with signal line SL, normally open relay contacts EGR-2 adaptedwhen closed to connect signal line terminal SL- with signal lineterminal SL-land normally open relay contacts EGR-3 adapted when closedto connect transmitter line terminal TL- to ground G.

Direct current supervisory relay circuitry The direct currentsupervisory relay circuitry DCR includes a relay coil DCR-C connectedacross battery H, and normally open relay contacts DCR-1 adapted whenclosed to connect a pilot lamp PL-9 across an alternating current sourceK.

Transmitter supervision and emergency connect relay circuits Thetransmitter supervisory relay circuit TSR includes a high impedancecurrent limiting device in the form of relay coil TSR-C connectedbetween transmitter line terminals LN- and LN}, and normally open relaycontacts TSR-1 connected to the positive side of battery H through relaycoil ECR-C of emergency connect relay circuit ECR. Relay contacts TSR-1are also connected to the negative side of battery H through a seriescircuit including normally closed transmitter test switch S-6A, normallyclosed relay contacts TAR-3, normally closed relay contacts PCR-4, andnormally closed restore switch S-ZA. Emergency connect relay circ-uitECR also includes normally open relay contacts ECR-1 connecting relaycoil ECR-C across battery H through normally closed restore switch S-2A,normally open relay contacts ECR-2 connecting transmitter line terminalsLN- and TL-, and normally open relay contacts ECR-3 connectingtransmitter terminals TL-land LN}-.

Detector line supervisory relay circuitry The detector line supervisoryrelay circuit DSR includes relay coil DSR-C and normally open relaycontacts DSR-1 and DSR-2. As illustrated in FIGURE 1, as well as inFIGURE 3, relay coil DSR-C is in series circuit with detector line DLtogether with line current adjusting rhetostat RV-3 and milliampereammeter 22. Nor mally open relay contacts DSR-1 serve to connect a pilotlamp PL-7 across battery H. The normally open relay contacts DSR-2 servewhen closed to conduct a relay coil TBR-C of trouble relay circuit TBRacross battery H.

Trouble relay circuit The trouble relay circuit TBR, in addition torelay coil TBR-C, also includes normally closed relay contacts TBR-1 andnormally open relay contacts TBR-2. Trouble contacts TBR-2 when closedserve to connect a supervisory alarm lamp PL-11 and a trouble buzzer TBacross an alterating voltage source L. Also, a switch S-7 is providedhaving normally closed contacts S-7A and S-7B. Contacts S-7A serve toconnect trouble buzzer TB in parallel with lamp PL-11 and contacts S-7Bare connected in parallel with relay contacts TBR-2.

Alarm supervisory relay circuit The alarm supervisory relay circuit ASRhas, as illustrated in FIGURE 3, a relay coil ASR-C connected in seriescircuit in alarm line AL together with line current adjusting rheostatvRV-Z, ammeter 36, alarm devices AL-l, AL-Z and AL-3 across the outputcircuit of converter CV-2 through normally closed relay contacts SAR-3of the signal alarm relay circuit SAR. The alarm signal relay circuitASR also includes normally -open relay contacts ASR-l and ASR-2. Relaycontacts ASR-1 serve when closed to connect a pilot lamp PL-6 acrossbattery H, through normally closed relay contacts SAR-4 of signal alarmrelay circuit SAR. The relay contacts ASR-2 serve when closed to connectrelay coil TBR-C of trouble relay circuit TBR across `battery H. Aswitch S-S includes normally closed switch contacts S-SA and S-8B, andnormally open switch contacts S-8C and S-8D. Switch contacts S-SC whenclosed serve to short circuit normally closed contacts SAR-3 in alarmline AL to prevent transmission of current from converter CV-2 throughthe alarm circuit, if desired. When switch contacts S-SA and S-SB areopened, causing contacts S-SC and S-SD to become closed, a pilot lampPL-12 will be connected across battery H. In addition to the foregoing,the trouble relay coil TBR-C may be energized upon closure of normallyopen relay contacts SSR-1 or relay SSR. As illustrated in FIGURE 3,contacts SSR-2 serve when closed to connect pilot lamp PL-3 acrossbattery H.

General operation During the operation of the signaling system,supervisory current on the order of milliamperes normal-ly ilows throughsignal line SL, supervisory current on the order of 4() milliamperesnormally flows through the detector line DL, supervisory current on theorder of 10 milliamperes normally ows through the series circuitincluding transmitter lines TL and LN, and alarm supervisory current onthe order of 100 milliamperes normally ilows through alarm line AL. Thetransmitter line supervisory relay coil TSR-C connecting transmitterterminals LN+ to LN- is normally energized by the l0 milliampere currentiowing through the coil, whereby its magnetically associated relaycontacts TSR-1 are normally open, as shown in FIGURE 3. The l0milliampere current owing through the transmitter line is insuicient toenergize transmitter alarm relay coil TAR-C, therefore transmitter alarmrelay contacts TAR-2 are open and relay contacts TAR-1 are closed, asshown in FIGURE 3, short circuiting timing capacitor C-1 in pulsegenerator PG. Thus, the pulse generator PG is normally inoperative andthe transmitters XTR-1 through XTR-7 are normally deactivated.

Reference is now made to detector D in the detector line DL illustratedin FIGURE 1. The current normally owing through the detector line DLflows through coils 28 and 30 of detector relay DR in opposingdirections. Upon closure of detector contacts 32 in response to an alarmcondition, such as a smoke detection, heat detection, or the like, coil28 will become short circuited and the detector relay DR will becomeenergized, whereby its associated contacts 34 will become closed. Withrelay contacts 34 closed transmitter coil XT R-C of transmitter XTR-3will be connected directly across terminals TIH- and LN-, thereby shortcircuiting the high impedance relay coil TSR-C. The current flowingthrough the transmitter line will then increase in value sufficiently toenergize transmitter alarm relay coil TAR-C.

The transmitter alarm coil TAR-C may also be energized by connectingmovable contact 72 to stationary contact 76 of detector switch S-l,illustrated in FIGURE 2. With contact 72 in electrical engagement withstationary contact 76 current will flow from the positive side ofconverter CV-1 through normally closed pulse generator relay contactsPGR-1, transmitter alarm relay coil TAR- C, transmitter line terminalTL-l, through transmitter coil XTR-C, movable contact 64 to stationarycontact 66 of transfer switch S2, stationary contact 76 to movablecontact 72 of detector switch S-l, and through transmitter line terminalTL- to the negative side of converter CV-1. In this manner, transmittersupervisory relay coil TSR-C will be short circuited, whereby thecurrent flowing through transmitter line TL will increase sufficientlyin value to energize transmitter alarm relay coil TAR-C.

When transmitter alarm relay coil TAR-C becomes energized (see FIGURE3), its normally closed relay contacts TAR-1 will become opened, therebyremoving the previous short circuit path across timing capacitor C-1 ofpulse generator PG. Current will tiow from the positive side of lbatteryH, through resistors R-8, R-1, variable resistors 106 and 104 to chargecapacitor C-1. Referring now to the waveforms of voltage versus time inFIG- URES 4A through 4E, it will be noted that at time to relay coilTAR-C is energized, as illustrated by waveform VTAR C in FIGURE 4A. Whenrelay coil TAR-C becomes energized, capacitor C-l will commence chargingin accordance with the voltage waveform V04, illustrated in FIGURE 4B,toward the peak point voltage Vp, having a waveform as illustrated bythe dotted line in FIG- URE 4B, of unijunction transistor Q-l. After aperiod of time t1 in accordance with the RC time constant determined bythe values of resistors R-8, R-1, variable resistors 106 and 104 andcapacitor C-1, the voltage V04 across capacitor C-1 will attain thelevel of the peak point voltage Vp, whereupon the emitter of transistorQ-l will become forward biased and the dynamic resistance between theemitter and base B-l will decrease to an eX- ceedingly small value sothat the capacitor C-l will discharge through the emitter to base B-1and load resistor R-3. The voltage developed across load resistor R-3when capacitor C-1 discharges will be sucient in magnitude to triggerthe bistable multivibrator circuit 100. Each time that siliconcontrolled rectifier Q-3 is conducting current, both relay coil PCR-Cand relay coil PGR-C will become energized. When relay coil PGR-Cbecomes energized, normally closed contacts PGR-1 will open presentingan open circuit in the transmitter line TL. This will de-energizetransmitter coil XTR-C and pawl 42 will, in a conventional manner,displace the ratchet wheel 40 one step in the direction shown by thearrow in FIGURE 2. When the ratchet wheel has moved one step the movablecontact 64 of transfer switch S-2 will electrically engage stationarycontact 68 deactivating the detector switch circuit; however, themovable contact 90 of off-normal switch S-4 will engage stationarycontact 92 thereby maintaining electrical circuit connection betweentransmitter lines TL and LN through coil XTR-C.

With reference to the waveforms illustrated in FIG- URES 4C through 4E,it will be noted that when capacitor C-1 is discharged after completinga charging period for a time shown by t1, the pulse generator PGenergized the pulse generator relay coil PGR-C, as indicated by thefirst pulse P-1 of the voltage waveform VPGR C, illustrated in FIGURE4C. Also in FIGURE 4D it will be noted that when the pulse generatorrelay coil PGR-C is energized the transmitter coil XTR-C isde-energized, as evidenced by the waveform VXTR C. Also, in the eventthat upon the first step of the ratchet wheel 40 the code wheel signalcontacts SL-l are opened, the Signal alarm relay coil SAR-C will bede-energized, as evidenced by the waveform VSAEC in FIGURE 4E.

When the pulse control relay coil PCR-C becomes energized its contactsPCR-2 and PCR-3 will become closed, and its normally closed contactsPCR-1 will become open. When the transmitter alarm relay coil TAR-Cbecomes de-energized upon opening of pulse generator contacts PGR-1, itscontacts TAR-1 will close, but will not short circuit the timingcapacitor C-1 because contacts PCR-1 are still open due to the slowrelease characteristic of relay PCR. C-1 will therefore immediatelystart to recharge toward the peak point voltage Vp of unijunctiontransistor Q-1; however, the charging path for capacitor C-1 will notinclude variable resistor 104 which becomes short circuited upon closureof contacts PCR-2, but rather includes resistors R-S, R-1, variableresistor 106, now closed contacts PCR-2 and resistor R-9. The RC timeconstant of the new charging circuit is much shorter than that of the RCtime constant when variable resistor 104 is in the charging circuit.Thus, after a period of capacitor charging, evidenced by the time t2,which is much shorter than t1, the voltage CC 1 across capacitor C-1will attain a level equal to the peak point voltage Vp of unijunctiontransistor Q-l, whereupon the capacitor will again discharge through theemitter to base B-l of the transistor to develop a second triggervoltage pulse across load resistor R-3. This trigger pulse voltage willbe sucient to change the state of multivibrator so that siliconcontrolled rectier Q-3 -becomes nonconductive and silicon controlledrectifier Q-Z becomes conductive. Thus, pulse generator relay coil PCR-Cwill be de-energized as its previous current path through the anode tocathode circuit of rectier Q-3 has been removed. The relay contactsPGR-1 in the transmitter line TL will become closed and relay coil TAR-Cwill become energized. When relay coil TAR-C becomes energized itsnormally open contacts TAR-2 will become closed maintaining relay coilPCR-C energized since the time for its relay contacts PCR-3 to becomeopen is of longer duration than the time required for relay contactsTAR-2 to become energized when rectifier Q-3 becomes nonconductive.Thus, the relay coil PCR-C is normally energized during the pulsingoperation of the signal system so long as relay coil TAR-C becomesenergized immediately following closure of normally closed pulsegenerator contacts PGR-1.

Relaxation oscillator 102 will continue to oscillate so long as TAR-2contacts are closed by energization of relay coil TAR-C after eachopening and then closure of relay contacts PGR-1. When the transmitterXTR-1 completes its cycle of operation, the transfer switch contacts S-2and ofi-normal switch contacts S-4 and the detector switch contacts S-1will be in the positions illustrated in FIGURE 2. This will occur at atime when the controlled rectier Q-3 in the pulse generator isconductive and PGR1 is holding the transmitter line open. When Q-S nextbecomes nonconductive and PGR-C becomes de-energized, PGR-1 will closethe transmitter line which now includes the high resistance coil TSR-C.The value of the current flowing in transmitter line TL will then returnt0 its normal value on the order of l0 milliamperes. Thus, relay coilTAR-C of transmitter alarm relay circuit TAR will not become energizedby the current iiowing therethrough and its contacts TAR-1 will closeand its contacts TAR-2 will open. Failure of TAR to close its contactsTAR-2 will allow the slow release relay PCR to release. Its contactsPCR-3 and PCR-2 will then open and its contacts PCR-1 will close.Accordingly, the timing capacitor C-1 in the unijunction relaxationoscillator 102 of pulse generator PG will become short circuited and thepulse generator will cease to operate.

Operation of the coding mechanism When the pulse generator PG istransmitting a train of time spaced voltage pulses, as evidenced by thewaveform VXTR C in FIGURE 4D, the transmitter coil XTR-C in transmitterXTR-1 will alternately become energized and de-energized. Each timetransmitter coil XTR-C of transmitter XTR-1 (see FIGURE 2) is energizedand then deenergized, ratchet motor 38 will step one step. If the codewheel signaling contacts SL-1 are closed by a cam lobe 58 during theperiod when transmitter alarm relay coil TAR-C is energized, thencurrent will ow through the signal line SL to maintain the signal alarmrelay coil SAR-C energized. However, if during this period a cam 1 1lobe 58 does not maintain switching contacts SL-1 closed, then nocurrent will ow through the signal line SL and, hence, the .signal alarmrelay coil SAR-C will be deenergized. The waveform of the voltage acrosssignal alarm relay coil SAR-C may take the form, for example as thatillustrated in FIGURE 4E, from which it will be noted that a code of twopulses, a space and then a third pulse has been transmitted fromtransmitter XTR-1 to thecentral station. The console recorder CR, whichmay take various forms, is responsive to the energization andde-energization of relay coil SAR-C to print a code corresponding withwaveform VSAR C, Thus, with reference to FIGURE 3, it will be noted thatwhen coil SAR-C is energized its associated relay contacts SAR-2 will beopen, as shown, and when the coil becomes de-energized the contactsSAR-2 will close to energize the console recorder CR.

Noninterference operation with conventional transmitters During theoperation of the signaling system illustrated in FIGURE l, it ispossible that one of the conventional tire alarm transmitters A or Bwill have been actuated to commence transmitting coded signal impulsesto the central station C when one of the transmitters XTR-1 throughXTR-7 is activated by an automatic or manual closure of contact 72 withcontact 76 of detector switch S-1 (see FIGURE 2). Transmitters A and Bare conventional standard re alarm transmitters and preferably take theform of positive, noninterfering, successive, automatic grounding,prewound clockwork driven transmitters, such as E. W. Bliss Company,Gamewell Divisions Three Fold Manual or Automatic Box, catalog 7000(Manual) and 9000 (Master), Series. For purposes of simplicity, thetransmitters may be schematically illustrated as including normallyclosed switches 18 and 20, which upon actuation of the transmitter willopen and close the signal line SL in accordance with a predeterminedcode representative of the transmitting re alarm transmitter. Thus, foreX- ample, if transmitter A has been activated a code wheel mechanismwithin the transmitter will open and close switch 18 to interrupt the100 milliampere current normally owing through signal line SL inaccordance with a predetermined code representative of transmitter A.Each time switch 18 is opened, the signal alarm relay coil SAR-C in thetransmitter signal line SL will become deenergized and its associatedrelay contacts SAR-2 will become closed to energize the console recorderCR. Thus, the console recorder CR willrecord a visual representation ofthe code transmitted by transmitter Ato the central station C.

If normally closed signaling contacts 18 of transmitter A are open whnetransmitter XTR-1 becomes activated, then relay coil TAR4C will becomeenergized due to the activation ofptransmitter XTR-1 and signal alarmrelay coil.SAR-C will be de-energized due to the interruption of'.current flow through the signal line SL upon opening of contacts 18.With relay coil TAR-C energized its normally closed contacts TAR-1 willbecome open, but timing capacitor C-1 will not be permitted to chargesince a short circuit across the capacitor will be completed throughrelay contacts SAR-1 which close upon de-energization of relay coilSAR-C. Upon the next closure of signal contacts 18 of transmitter A,relay coil TARC will still be energized since transmitter XTR-1 willstill be activated, but relay contacts SAR-1 will become opened therebyproviding an open circuit path across capacitor C-1 which will nowcommence to charge through the circuit including the positive side ofbattery H, through resistors R-S, R-l, Variable resistors 106 and 104,as illustrated by the waveform VC 1 in FIGURE 5C. However, beforesuicient time has elapsed for the voltage VC 1 across capacitor C-1 toattain the peak point voltage VP of unijunction transistor Q-1, thesignaling contacts 18 of transmitter A will again open, whereby thecapacitor will again be short circuited and will discharge throughresistor R-9, normally closed contacts PCR-1, normally. closed restoreswitch S-ZB and closed contacts SAR-1.0i relay SAR to the negative sideof Abattery H..Thus, the pulse generator PG will not commence operation.Referring now to the waveform illustrated :in FIGURE B of the voltageVSAR C across relay coil SAR-C, it-will be noted that contacts 18 oftransmitter A have alternatelyr opened and closed the signalline SL totransmit three pulses or breaks to the central .station- C, the lastbreak of which is elongated by contacts 18 remaining open'for the timeshown by t3. TheV time vt1 required for v'capacitor C-1 to charge to thepeak point voltageVp of transistor Q-1 is adjusted by means of variableresistor 104 sot-that it is greater than time t4, the time of closure-ofcontacts 18 vduring signaling operation. Thus this period t4wma'y bereferred to as a test period duringv which the ycentral station C willtest the signal line SL to determinewhether it should permit the pulsegenerator PG to begin operavtion and thereby permit transmitter XTR-1 totransmit coded signal impulses to the central station, or instead topermit a conventional transmitter, such as transmitter A, to completeits transmission of coded signal impulses; After the test period t4 hasterminated, the remaining impulses transmitted from transmitter A willtake the form of coded signal impulses representative'of transmitter'Aland these coded signal impulses will be recorded by console recorder CRin the manner describedV previously. After the transmitter A hascompleted transmitting its coded signal impulses to the central stationC, and providing the transmitter XTR is still activated, i.e.,transmitter alarm relay coil TAR-C is still energized, the timingcapacitor C-1 will charge to the peak point voltage Vp of unijunctiontransistor Q-l, in the manner described previously with reference toFIGURES 4A and 4B, so that transmitter XTR-1 will transmit its codedsignal impulses to the central station C.

Noninterference operation with system transmitters When transmitterXTR-1 becomes activated by closure of switch contact 72 with contact 76of detector switch S-1 (see FIGURE 2), current will ow from thetransmitter line terminal TL+ through transmitter coil XTR-C, transferswitch S-Z, contacts 76 and 72 of switch S-l, to the transmitter lineterminal TL-, as previously described. Current will also flow throughnoninterfe'rence coil NI-C in parallel with transmitter goil XTR- C,whereupon the noninterference coil will also become energized and itsassociated normally closed contacts NI-l will become opened. This placesdiode 96 inthe transmitter 'lin'e circuit to prevent current flow beyondtransmitter XT R-l to transmitters XTR-2 to XTR-7. Similarly, when theratchet motor 38 steps one step, contact 90 will engage contact 92 ofoff-normal switch S-4 and, thus',l current will no longer be permittedto flow from transmitter line terminal LN- throughthe path from thecathode s ide of the diode 74,`through contacts 82 and 80 ofswitcli'S-Z, through switch S-S when closed, and contacts 94 and 90, ofswitch S-4. Diode 74, therefore, serves to block cur-A rent flow froma'previous transmitter, i.e., fone closer to the central station thantransmitter XTRfl, through the path including terminal LN-,th'rough thediode74 to terminal TL- and, thence, to the negative side of converterCV-1. Transmitter XTR-1 will transmit its coded signal impulses to thecentral station C without inter ference from either a preceding or a.succeeding transmitter until such time that contact is againplaced inelectrical engagement with contact 94'l of off-normal switch S-4. Withreference to FIGURE 2, it will be noted" that upon a half revolution ofcam shaft 94 the wiper portion of contact 90 willvv be received by notch88y in the'of-normal cam wheel 56 so that the movable contact 90 becomesengaged with stationary contact 94 to'thereby short circuit diode 74.This will permit a preceding transmitter toy commence operation andsince in this position the olf-normal switch prevents current from owing13 through the transmitter XTR-C, as well as a noninterference coilNI-C, contacts Nl-l will close to short circuit diode 96 to permit asucceeding transmitter to commence operation.

Types of transmitter operation i The signaling system of the presentinvention may include separately or in combination various types ofsignaling transmitters, such as, for example, manual lire alarmtransmitters, automatic fire alarm transmitters, supervisory alarmtransmitters, and watch report station transmitters. Whereas thesetransmitters generally take the form as illustrated in FIGURE 2, they,nevertheless, operate in somewhat different manners. That is, atransmitter for a manual iire alarm should transmit four rounds of codedsignal impulses for each operation, with each round constitutingone-half revolution of cam shaft 44 of the ratchet motor 38 (see FIGURE2). During each operation of a manual fire alarm transmitter the codedsignal impulses transmitted to the central station will include apresignal representative of the nature of the transmitter signal,followed by a coded signal representative of the particular activatedtransmitting alarm box or transmitter. For the manual tire alarmtransmitters, the presignal and the following box number signal will bethe same for each transmitted signal round.

For automatic tire alarm transmitters, such as for heat or smokedetectors, sprinkler alarms, etc., the transmitter will transmit fiverounds and then stop until the alarm condition has been restored tonormal. The transmitter will then transmit one more round when the alarmcondition has been restored to normal. The presignal transmitted for thefirst five rounds will be representative of an alarm condition and thepresignal transmitted for the sixth round will be representative of anormal condition.

For supervisory alarm transmitters, such as for power ot, valve closed,pressure low, etc., the transmitter will transmit one round with apresignal representative of an abnormal condition. When this conditionis again normal, the transmitter will transmit one more round with apresignal representative of restoration to normal condition.

For watch report stations the transmitters will each transmit one roundfor each opeartion of the station. The presignal will indicate that thesignal is a watch report and will be the same for each operation of thetransmitter.

Geneva gear switch operation In the previous section of the descriptionof operation it was mentioned that the various transmitters may transmitvarious rounds of signal impulses to the central station C. Referringnow to FIGURE 2, it will be noted that when movable contact 71 engagescontact 73 of switch S-S, the Geneva gear switch S-3 will beinelfective, as is the case when it is desired that the cam shaft 44turn one-half revolution and then stop during which a presignal of analarm condition may be transmitted followed by a station identifyingsignal. If at a later time the condition has been restored to normal,the switch contact 72 will be displaced to engage contact 70 eithermanually or automatically, as desired, and the transmitter XTRHC coilwill become energized through movable contact 64 to stationary contact68 of transfer switch S-2, stationary contact 70 and movable contact 72of detector switch S-1.

Reference is now made to FIGURE 6 which illustrates a waveform ofamplitude versus revolutions, showing the closure pattern of contacts 90and 92 of olf-normal switch S-4 throughout the transmission of sixrounds R-1 through R-6 of coded signal impulses from transmitter XTR-1to the central station C. If it is desired that transmitter XTR-1transmit ve uninterrupted rounds of coded signal impulses to the centralstation C and then stop until the condition noted by the transmitterXTR-1 has been resored to normal before transmitting the last round R6,then the Geneva switch S-3 is activated by connecting contact 71 tocontact 75 of switch S-S. The Geneva gear 54 and its arrangement withpin 52 on Geneva gear actuating wheel 50 is well known to those skilledin the art and may be arranged so that cam lobe 78 will actuate Genevaswitch contact 80 once per revolution, or some desired multiple ofrevolution of shaft 44 and maintain contact 80 in engagement withcontact 84 until pin S2 again engages one of the teeth of the Genevagear. With reference to FIGURES 6A and 6B, the Geneva gear, for example,may be arranged to actuate switch arm 80 at a time corresponding with150 of angular revolution of cam shaft 44. Switch contact 80 may bemaintained in engagement with switch contact 84 until contact 80 ridesoff cam lobe 78 at, for example, 870 of the angular revolution of camshaft 44. This function is illustrated in FIGURE 6B, which illustratesthe period of closure of the Geneva switch contacts 80 and 84. So longas Geneva switch contacts 80 and 84 are in engagement, the otfnormalswitch S-4 will be short circuited and, hence, each time the pulsegenerator PG transmits a driving pulse to energize transmitter coilXTR-C the ratchet wheel motor 38 will be operative to step one step at atime without hindrance of the off-normal switch contacts, as describedin the previous descriptions of operation. When the Geneva gear 54 isactuated again at, for example, 870 of angular revolution of shaft 44,the Geneva gear switch contact 80 will return to engage contact 82whereby the off-normal switch S-4 will no longer be short circuited.This function can, 'for example, take place during the period that roundR-5 of the signal impulses are being transmitted from the transmitterXTR-1 to the central station C. Upon the completion of signal impulsesof round R-S the off-normal switch will again provide an open circuitpath for the transmitter coil XTR-C which will not be energized againuntil the detector switch S-1 is returned to its normal condition, i.e.,with switch contact 72 in engagement with switch contact 70.

Broken signal line operation During the operation of the signalingsystem it is possible that signaling line SL will become broken,presenting an open circuit for a duration greater than that of an opencircuit interval of the coded signal impulses transmitted from atransmitter to the central station C. When an open circuit is present inthe signaling line SL, signal alarm relay coil SAR-C will becomede-energized and its normally open relay contacts SAR-2 will becomeclosed to energize the ground time delay circuit GTD. The time delayafforded by the unijunction relaxation oscillator is increased by thefree running oscillator circuit 107, the operation of which is wellknown to those skilled in the art, which serves to momentarily drop thepeak point voltage of unijunction transistor Q-4, allowing peak pointcurrent to be supplied from capacitor C-6 rather than through thecircuit including resistors RV-4 and R-11. After the time delay hasexpired capacitor C-6 will discharge through the emitter to base B-1 ofunijunction transistor Q-4 to develop a trigger pulse across resistorR-12, which when applied to the gate of silicon controlled rectifier Q-6will cause the rectier to become forward biased and conductive. Currentwill then ow from the positive side of battery H, through relay coilEGR-C of emergency relay circuit EGR and also through lamp PL-4 toenergize the lamp, through the anode to cathode circuit of siliconcontrolled rectifier Q-6, and through the normally closed restore switchS-2A to the negative side of battery H. The emergency ground relaycontacts EGR-1 will thus become open and the contacts EGR-2 and EGR-3will become closed, whereby signal line terminals SL- and SL-lareconnected together and transmitter line terminal TL-, i.e., the negativeside of converter CV-1, is connected to ground G. Thus, as isconventional in the use of signaling systems of the type described inthis patent application, the negative side of the power supply has beengrounded upon a broken signal line to permit broken line operation fromthe signaling contacts of the transmitters through the ground connectionto complete the signaling line circuit. The emergency ground relay coilEGR-C will remain energized until it is de energized by a momentaryopening o'f restore switch S-ZA.

Broken transmitter line operation During the operation of the signalingsystem it is possible that an open circuit due to a break will occur inthe transmitter line circuit, whereby the normally energized transmittersupervisory relay coil TSR-C in the transmitter line circuit will becomede-energized. Normally open contacts TSR-1 will become closed to connectthe emergency -connect relay coil ECR-C across battery H, through closedswitch S-6A, the normally closed contacts TAR-3 and PCR4, and throughthe normally closed restore switch S-2A. Thus, relay coil ECR-C will beenergized and its associated lamp PL-S will also be energized to presenta visual indication to an operator that the transmitter line is broken.Also, the normally closed contacts ECR-1, ECR-2 and ECR-3 of theemergency connect relay ECR will become closed connecting transmitterline terminal TL+ to terminal LN-iand terminal LN- to terminal TL-, aswell as connecting the relay coil ECR-C directly to the restore switchS-ZA, thereby providing lockup circuit for the relay coil ECR-C so longas restore switch S-ZA is closed. The normally closed contacts PCR-4 andTAR-3 of the pulse relay control circuit PCR and the transmitter alarmrelay control circuit TAR, respectively, serve to prevent energizationof relay coil ECR-C during normal signal transmission of the signalsystem. Further, the transmitter test switch S-6A serves to preventenergization of emergency connect relay coil ECR-C when it is desired totest the operation of the transmitters, i.e., upon opening of switchS-6A. It should be noted that normally closed contacts TAR-3 and PCR-4,as well as normally closed switch S-6A may serve to prevent energizationof relay coil ECR-C, but will not de-energize the coil if it hadpreviously become energized and then locked up through contacts ECR-1.After relay coil ECR-C has been energized it can be de-energized only bymomentarily opening of restore switch S-2A.

Detector line alarm operation The detector line starting relays in thenormally closed detector supervisory circuit DL are two coil, singlepole, double throw relays with the two coils, i.e., 28 and 30, connectedin series opposition so that when both coils are energized by current owtherethrough the energization of the coils will oppose each other andthe associated relay contacts 34 will be open. If for some reason duringthe operation of the signaling system the detector line DL has a brokencircuit in its series path, the detector supervisory relay coil DSR-Cwill become de-energized and its normally open contacts DSR-1 and DSR-2will become closed. Thus, the pilot lamp PL-7 will become energized atthe central station presenting a visual indication of the disruption ofthe detector line. Current will ilow from the positive side of battery Hthrough the trouble relay coil TBR-C, the now closed detectorsupervisory contacts DSR-2 to the negative side of battery H. Thus, thetrouble relay contacts TBR-1 will become opened and the normally closedcontacts TBR-2 will become closed, whereby trouble indicating lampPL-11, as well as the trouble buzzer TB, will become energizedpresenting -visual and audible indications to an operator of troublewithin the system. The operator upon noting that lamp PL-7 is energizedwill be aware that the trouble noted is that of a break in the circuitof the detector line DL.

Signal supervisory relay circuit operation During the operation of thesignaling system it is possible that a break will occur in the signalingline SL, whereupon the signal supervisory relay coil SSR-C will becomede-energized, causing its associated relay contacts SSR-1 and SSR-2 tobecome closed. Upon closure 0f contacts SSR-1 and SSR-2 the signalsupervisory alarm lamp PL-3 will become energized and the trouble coilTBR-C will become energized causing trouble lamp PL- 11, as well astrouble buzzer TB, to be energized. Thus, an operator will be providedwith visual and audible indica tions of a trouble condition in thesystem, and upon observing the various lamps he will note that lamp PL-3is energized, indicative that the troubleV condition is a break in thesupervisory line SL.

Alarm supervisory relay circuit operation The alarm supervisory relaycoil ASR-C is normally energized vby the milliarnpere current flowingthrough the alarm circuit. If for some reason the alarm circuit isbroken, the coil ASR-C will become de-energized whereby its associatedrelay contacts ASR-1 and ASR-2 will become closed, and in a mannersimilar to that as described hereinabove, the pilot lamp PL-6, `as wellas the pilot lamp PL-ll and trouble buzzer TB, will all become energizedproviding an operator with audible and visual indications of the troublecondition existing in alarm line AL. To prevent a trouble indicationwhen the alarm circuit is open by a signal repeated into it, thenormally closed relay contacts SAR-4 of relay SAR are connected inseries with normally open contacts ASR-1 of relay coil ASR so that pilotlamps PL-6, PL-11 and trouble buzzer TB will not become energized duringan alarm transmission. The trouble buzzer TB may be silenced by closureof switch contacts S-7B and opening of contacts S-7A. When the relaytrouble coil TBR-C is restored to its normal condition, the buzzer willagain sound and can be silenced by restoring the switch S-7 to theposition as shown in FIGURE 3, i.e., closure of contacts S-7A andopening of contacts S-7B. In the event that alarm transmission over thealarm circuit AL is not desired, the switch S-8 may be thrown to itsalarm silencing position, i.e., closure of contacts S-SC and S-SD andopening of contacts S-8A and S-SB. This will cause pilot lamp PL-lZ tobe energized and the now closed contacts S-SC will short contacts SAR-3of the signal alarm relay coil SAR so that signals will not be repeatedinto the alarm circuit. The pilot lamp PL-12 will be maintainedenergized by contacts S-SD of the switch until the switch is restored toits normal position.

Direct current relay alarm circuit operation During the operation of thesignaling system it is possible that battery H will fail, and,accordingly, the norrnally energized relay coil DCR-C of the directcurrent relay DCR will become de-energized, whereby its associatedcontacts DCR-1 will close. With contacts DCR-1 closed, pilot lamp PL-9will become energized from an alternate current supply, such asindicated at K, providing a Visual indication of the failure of thebattery voltage.

In accordance with a lpreferred embodiment of the invention, the valuesand types of components illustrated in the drawings are found in TableI.

TABLE I Component: Component value or type Capacitor C-1 microfarads-..20 Capacitor C-2 do 0.047 Capacitor C-3 do 0.047 Capacitor C-4 ldo..0.33 Capacitor C-S do 0.33 Silicon controlled rectifier Q-Z i CZOFSilicon controlled rectifier Q-3 C20F Unijunction transistor Q-1 2N2646Zener diode Z-1 volts 12 Diodes D-l, D-2, D-3, D-4 (0.5 amp.)

volts-.. 200 Resistor R-1 kilohms 4.7 Resistor R-2 do 1.0 Resistor R-Sohms 33 Component-Continued Component value or type Resistor R-4 kilohms22 Resistor R-S ohms-- 470 Resistor R-6 do 330 Resistor R-7 do 330Resistor R-8 do 470 Resistor R-9 do 33 Variable resistor 104 kilohms-..200 Variable resistor 106 do 100 Battery H (D.C.) volts-.. 24

Output voltage of converters Cv-l, CV-z, Cv-s (DC.) d 110 vRelay coilPCR-C ohms. 600 Relay coil PGR-C do 480 Relay coil TAR-C do 480 Relaycoil SAR-C do 120 Relay coil SSR-C do- 120 Relay coil DCR-C do 480Variable resistor RV-1 do- 1000 Relay coil ASR-C do 120 Relay coil DSR-Cdo 480 Relay coil TBR-C do 480 Resistor R- kilohms 1.2 Variable resistorR-4 megohms-- 3 Resistor R-11 do.. 1 Timing capacitor C-6 microfarads 2OUnijunction transistor Q-4 2N2646 Resistor R-13 kilohm-.. 1 ResistorR-12 ohms-- 33 Capacitor C-7 microfarad-.. 0.001 Resistor R-lSkilohms-.. 100 Capacitor C-8 microfarad-- 0.01 Resistor R-14 kilohm-- 1Unijunction transistor Q-S 2N2646 Capacitor C-9 microfarad-- 0.01Silicon controlled rectier Q6 2N2323 Zener diode Z-2 Volts 39 Relay coilEGR-C ohms-- 480 Relay coil TSR-C kilohms 10 Relay coil ECR-C ohms-- 480Transmitter coils XTR-C do 1600 Detector relay coil DR 'do.. 70 BatteryH (D.C., 12 cell) .volts.. 24

Although the invention has been shown in connection with a preferredembodiment, it will be readily apparent to those skilled in the art thatvarious changes in form and arrangements of parts may be made to suitrequirements without departing from the spirit and scope of theinvention.

I claim:

1. A non-interfering signaling system comprising:

a plurality of remotely located, remotely powered system transmitters,each including code signaling means, driving means for driving said codesignaling means, and control means for actuating said driving means;

a self-powered conventional lire alarm transmitter having normallyclosed signaling contacts; circuit means electrically connecting saidsignaling contacts in series with the signaling means of said systemtransmitters and including a signal line conductor extending from acentral station;

a central station pulse generator means, located at said central stationfor transmitting driving impulses to the driving means of an activatedsystem transmitter through circuit means including a pair of conductorsextending from said central station to said system transmitters; and,

pulse generator control means located at said central station andcoupled to said pulse generator means, said pulse generator controlmeans including circuit means for energizing said pulse generator meansonly when a system transmitter is activated after a predetermined periodof time has elapsed from the last actuation of a said conventional alarmtransmitter so that non-interfering operation is obtained between saidsystem transmitters and said conventional alarm transmitter. 2. Asignaling system as set forth in claim 1 wherein said pulse generatorcontrol means includes circuit means for timing said predeterminedperiod of time upon actuation of a said conventional fire alarmtransmitter before energizing said pulse generator, said predeterminedperiod of time being greater than the time duration of a closed circuitin said signal line conductor circuit due to a closure of said re alarmtransmitter signaling contacts during signaling operation to preventenergization of an activated system transmitter until said conventionallire alarm transmitter completes its signaling operation.

3. A signaling system including rst, second and third conductors eachdefining a loop extending from a central station;

at least one system transmitter having drive means and code signalingmeans driven by the drive means;

control means for said system transmitter for connecting said systemtransmitter drive means across said rst and second conductors;

pulse generator means for developing a train of time spaced impulses fortransmission through said first and second conductors to energize saidsystem transmitter drive means;

said code signaling means of said system transmitter being connected inseries circuit with said third conductor for transmitting coded signalimpulses to said central station upon energization of said pulsegenerator;

said third conductor being connected with a conventional tire alarmtransmitter including a normally closed signaling switch being connectedin a series circuit with said third conductor, said signaling switchupon actuation of said tire alarm transmitter opening and closing saidseries circuit in accordance with a predetermined code; and,

pulse generator control means for energizing said pulse generator meanswhen said system transmitter is activated by said control means and nosaid conventional tire alarm transmitter is actuated,

4. A signaling system as set forth in claim 3 including timing means fortiming a predetermined period of time upon actuation of said systemtransmitter and means responsive to the termination of saidpredetermined time to energize said pulse generator, said predeterminedtime being greater than the time duration of a closed circuit intervalin said third conductor series circuit due to closing of saidconventional lire alarm signaling switch during signaling operatori tothereby prevent said pulse generator from beng energized until saidconventional tire alarm transmitter completes its signaling operation.

5. A signaling system as set forth in claim 4 including a rst normallyclosed switch deactivating said timing means when no said systemtransmitter is activated and permitting activation of said timing meanswhen a said system transmitter becomes activated.

6. A signaling system as set forth in claim 4 including a secondnormally open switch deactivating said timing means when said thirdconductor circuit is open and permitting activation of said timing meanswhen said circuit is closed.

7. A signaling system as set forth in claim 4 including a first normallyclosed switch deactivating said timing means when no said systemtransmitter is activated and permitting activation of said timing meanswhen a said system transmitter becomes activated, and a second normallyopen switch deactivating said timing means when said third conductorcircuit is open and permitting activation of said timing means when saidcircuit is closed.

8. A signaling system as set forth in claim 3 wherein said pulsegenerator includes a bistable multivibrator circuit and a relaxationoscillator circuit for developing a train of time spaced trigger pulsesfor triggering said multivibrator from one state to the other state,said oscillator 19 circuit including a timing capacitor and a capacitorcharging circuit for charging said capacitor for a predetermined timetoa predetermined voltage at which time said capacitor discharges andsaid oscillator develops a said trigger pulse;

said pulse generator control means including circuit means forpreventing said timing capacitor from charging-toward said predeterminedvoltage when no vsaid system Itransmitter is activated and to permitsaid timing capacitor to charge when a said system 'transmitter becomesactivated. 9. A signaling system as set forth in claim 8 wherein saidpulse generator control circuit includes a iirst norrnally closed switchshort circuiting said timing capacitor, said switch being open when asaid system transmitter is activated to permit said timing capacitor tocharge.

10. A signaling system as set forth in claim 9 wherein a'normallyde-e'nergized relay coil magnetically associated with said rst switch isconnected in series circuit with said Virst `conductor, said first andsecond conductors being connected together in series circuit through ahigh impedance current limiting device so that current flowing throughthe series circuit of said iirst and second conductors is normallyinsuicient to energize said relay coil, said system transmitter controlmeans adapted to short circuit said high imperdance device to therebyincrease said current sufficiently to energize said relay coil, whereby'said irs't switch will become opened permitting said .timing capacitorto charge to said predetermined voltage and thereby trigger saidmultivibrator.

11. A signaling system as set forth in claim 9- including a secondnormally open switch connected in parallel with said rst switch, saidswitch being closed to prevent said capacitor from charging whenever anopen circuit exists in said third conductor series circuit.

12. A signaling system assetA forth in claim 11 wherein a normallyenergized relay coil magnetically associated with said' second switch isconnected in series circuit with said third conductor so that upon anopen circuit in said third conductor said relay coil will becomede-energized and its associated second switch will become closed toprevent said timing capacitor from charging.

13. A signaling system as set forth in claim 3 wherein said controlmeans includes a relay having a pair of relay contacts connected inseries with said driving means between said rst and second conductorsand a pair of relay coils connected together in series opposition, saidrelay coils being connected in series With a detector loop conductorhaving Adirect current normally owing therethrough, and one of saidrelay coils being connected in parallel -with -a normally open detectorswitch which when closed short circuits the said one coil, whereby theother of said relay coils will become energized to close said pair ofrelay contacts to thereby complete a circuit with said driving meansacross said rst and second conductors.

References Cited UNITED STATES PATENTS 2,355,934 8/1944 weld 3404-2952,492,043 12/1949 Holmes 340-287 2,997,665 s/1961 syn/an 328-2062,699,541 1/1955 ward 340-293 THOMAS B. HABECKER, Prmmy Examiner.

CHARLES M. MARMELSTEIN, Assistant Examiner.

U.S. Cl. X.R.

